Information Useful for
Working Out RFI Problems

In the US, a TV channel is a 6 MHz wide chunk of bandspace.
The bottom edge of the over-the-air channel 2 is 54 MHz and the
upper edge is 60 MHz. Within this 6 MHz space is a video carrier,
a color carrier, and an audio carrier.

The frequency of the video carrier is 1.25 MHz above the lower
edge, so for TV Channel 2 the video is at 55.25 MHz.

The color carrier is approx. 3.58 MHz above the video carrier
(N.B. not the lower edge), so for TV Channel 2 it is 58.83 MHz.

The audio carrier is 4.5 MHz above the video carrier, so for
TV Channel 2 it is 59.75 MHz.

The reason I mention all of this is that you have to be
careful to note how a channel frequency is being specified. The
two common methods are

Specifying the lower edge (e.g. 54 MHz, but often as a
range of lower edge to upper edge like 54-60 MHz)

Specifying the frequency of the video carrier (e.g. 55.25
MHz).

In the following lists I always use the latter method,
specifying the video carrier.

CATV has channels with frequencies below channel 2. They are
designated T-7 (tee seven or tee dash seven) through T-14 and are
usually used for transmission in the reverse direction. If your
local city council meeting is broadcast live, the camera is being
modulated onto one of those T channels and sent back up to the
cable system headend whereupon it is broadcast outbound on the
community cable access channel.

In the list I have some channels with the designation A-1 (A
minus one, not A dash one) through A-8. They are so designated
because their frequencies immediately precede that of the CATV
channel known as A.

In the CATV listing, the column labeled Common gives the
common industry parlance for that channel. The next column
labeled EIA gives the new EIA standardized designation. Column
STD shows the standard CATV frequency which usually matches IRC.
IRC stands for Incrementally Related Carrier and means that the lower edge of the channel space is on the nice, round-numbered
boundary such as 54 MHz, 60 MHz, 66 MHz etc. HRC stands for
Harmonically Related Carrier, and as you can see means that it is
the video carrier that is assigned the nice round number (6 MHz
harmonics, hence). Some cable systems use IRC, some use HRC.

The number of channels on a given cable system varies. Very
old systems might only go up to 300 or 350 MHz. Most common in
the past ten years or so is 450 MHz. Newer systems may be 550
MHz. The latest and greatest with any meaningful installed base
is 800 or 860 MHz (somebody correct me), but it is rare and
pricey. The list herein only goes up to 550 MHz.

FM radio frequencies are thrown in for good measure.

This stuff was gathered from several sources. My thanks to all
of them. Error reports are welcome.